Lung cancer is the most common cause of cancer death in the United States, accounting for more life lost than breast, prostate, colon and rectal cancer combined. Of the estimated 190,000 individuals who are diagnosed each year, over 180,000 succumb to the disease. Increasing insight into the molecular basis of lung cancer pathogenesis offers hope to combat this disease. Lung cancer development and progression involves the inactivation of tumor suppressor genes and activation of oncogenes. While the accumulation of genetic alterations has been shown to be involved in the progression of lung epithelial cells from hyperplasia, metaplasia, dysplasia, carcinoma in situ, invasive carcinoma, and finally metastatic carcinoma, recent work in the previous funding period of this SPORE project has demonstrated that epigenetic changes represent another important molecular change in lung cancer. With that background, the specific aims of the current proposal are: Specific aim 1. To utilize a newly derived microarray approach to identify novel hypermethylated genes which will help comprise methylation marker panels providing for full coverage of the non-small cell lung cancer genome. Specific aim 2. To utilize the marker panels from specific aim 1 to develop an epigenetic progression model based upon studies of precursor lesions and early stage lung cancer. Specific aim 3. To test the epigenetic marker panels for their efficacy as prognostic markers to identify patients with Stage I non-small cell lung cancer at very high risk for rapid disease recurrence. case-control study comparing sputum samples from 33 incident cases and their matched controls was conducted. The presence of any of four methylation markers examined was associated with a 6.3-fold increase in the risk for lung cancer. Moderate atypia or worse in sputum was also associated with a 4.1-fold increase in the relative risk for lung cancer over this time period. Interestingly, the methylation markers and cytology were not highly correlated with each other, though each was predictive of lung cancer risk, hence the two biomarkers were synergistic in conveying a 13.8-fold increase in relative risk. Through this cohort and a Phase II chemoprevention trial, studies with appropriate power will be designed to test specific hypotheses related to prediction of cancer risk and monitoring of chemoprevention interventions. This project is an inter-SPORE collaboration with Colorado that links clinical and epidemiologic findings with the development of promoter hypermethylation as molecular markers through the following three specific aims. Specific aim 1 will conduct a nested, case-control study within the Colorado cohort to evaluate longitudinally the ability to detect in sputum genes inactivated by methylation as biomarkers for predicting lung cancer risk either alone or in combination. Specific aim 2 will examine the dynamics of the field cancerization process by determining the concordance between methylation changes detected in sputum and bronchial biopsies from the same subject. Specific aim 3 will determine whether a panel of methylation markers can be used to predict the efficacy of the chemopreventive agent Iloprost in a randomized Phase II study through evaluation of bronchial biopsies and sputum collected at study entry and following completion of the intervention.